I do not think I was ever a young mom...although I felt young! I had my first child at 28... and my last at 32.. so I still feel young but in the realm of motherhood my age is balancing toward to old side.
One thing I can say is that age has afforded me more stability. I was able to find lucrative WAH jobs since I had my college education out of the way already and being older gave me more patience than what i would have had if I were younger.
Now saying all that ... I do not think anyone is ever ready for the changes that occur during motherhood mentally, physically...etc... regardless of age!